Vibration suppression may be important in any field where performance, precision, or durability may be affected by unwanted movement. Although it is critically important in aerospace applications, vibration suppression may also be employed to advantage in terrestrial transportation, manufacturing, manufactured goods (e.g., computer disk drives), metrological instrumentation and medical instruments, for example. Passive damping, which reduces a structure's vibration amplitudes at resonances, is one primary means of suppressing unwanted vibrations. By reducing the amplitude of vibration amplitudes at resonances, damping decreases stresses, displacements, fatigue, and sound radiation. Vibration isolation is another major approach to reduce the vibration effects on payloads and structures. Vibration isolation acts as a filter to reduce the transmission of vibration energy across the isolator. Vibration isolators are used between two structures or components to isolate motion changes of one component to the other. Vibration isolation systems also require passive damping to damp the resonances of the payload at the “isolation or resonance frequencies”.
U.S. Pat. No. 6,199,801 discloses a passively damped vibration isolation device with high strength and linear-elastic performance. The device of U.S. Pat. No. 6,199,801 remains relatively stiff against lateral loading as compared to its longitudinal loading.
U.S. Pat. No. 6,290,183 discloses a three-axis vibration isolation device that provides independently controllable, high strength, linearly elastic, multiple-axis compliance but with some sacrifice to longitudinal compactness. Damping within the device is also limited to the constrained-layer-on-beam-bending damping approach of the time, and effective primarily for longitudinal motions.
U.S. Pat. No. 7,249,756 addresses the need for a passive, highly damped vibration isolation device which provides independent and widely controllable compliance in all directions of vibration loading without sacrifice to strength and linearity of behavior, and without sacrifice to compactness or weight. The device of U.S. Pat. No. 7,249,756 is a low profile, passively and highly damped, vibration isolation mount which in multiplicity provides a complete vibration load isolation mounting system. It provides an independently determinable compliance in all directions of vibration loading without sacrifice to strength and linearity of behavior, and without significant sacrifice to compactness of the payload-vehicle interface or to weight. It provides substantial damping and resulting reduction in vibration load transmission from support base to payload by utilizing a shear wall type constrained layer damping. Each of U.S. Pat. Nos. 6,199,801, 6,290,183 and 7,249,756 are incorporated in their entirety herein by reference.